Cirrus Logic EP93xx - Manual (Page 297)

DS785UM1 8-33
Copyright 2007 Cirrus Logic
Graphics Accelerator
EP93xx User’s Guide
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DYDIR = ‘0’ - Down in Y
For a Line Draw function:
DXDIR = ‘1’ - If X2 > X1
DXDIR = ‘0’ - If X2 <= X1
DYDIR = ‘1’ - If Y2 > Y1
DYDIR = ‘0’ - If Y2 <= Y1
LINE: Line Draw Function Enable - Read/Write
‘0’ - Line draw disabled
‘1’ - Line draw enabled
Reading this bit returns a valid value only when EN = '1'.
FILL: FILL Function Enable - Read/Write
‘0’ - Fill disabled
‘1’ - Fill (with mask value) enabled
Reading this bit returns a valid value only when EN = '1'.
TRANS: Transparency Enable - Read/Write
‘0’ - Transparency disabled
‘1’ - Transparency enabled
Reading this bit returns a valid value only when EN = '1'.
INTEN: Graphics Accelerator Interrupt Enable - Read/Write
‘0’ - Interrupt disabled
‘1’ - Interrupt enabled
EN: Initiate Graphics Acceleration Function - Read/Write
Read:
‘0’ - Graphics processing completed
‘1’ - Graphics processing in progress
Write:
‘0’ - Terminate current graphics processing function
‘1’ - Initiate graphics processing function